Telescopic support for armrest

ABSTRACT

A telescopic support is provided for an armrest of a chair. The telescopic support includes a lower tube, an upper tube and a helical spring. The lower tube is installed on the chair. The upper tube telescopically receives the lower tube and supports the armrest. The helical spring is axially positioned in the upper tube and compressed between the upper tube and the lower tube for automatically and smoothly lifting the upper tube from the lower tube.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates to an armrest and, more particularly, to a telescopic support for an armrest.

2. Related Prior Art

Disclosed in Taiwanese Patent Publication no. 451658 is a telescopic support for an armrest 4. The telescopic support includes a first tube 1, a second tube 2 telescopically inserted in the first tube 1 and a control device 3 provided between the first tube 1 and the second tube 2. The first tube 1 includes two racks 111 and 121. The control device 3 includes two toothed wheels 32 and 33 attached to the second tube 2. The toothed wheels 32 and 33 can be engaged with two racks 111 and 121 of the first tube 1. A detent 34 is pushed to the toothed wheels 32 and 33 by a spring 36. The detent 34 includes two toothed portions 341 and 342 for engagement with the toothed wheels 32 and 33 so that the toothed wheels 32 and 33 can not rotate. Hence, the racks 111 and 121 can neither be lifted nor lowered, i.e., the armrest 4 can neither be lifted nor lowered. The detent 34 is connected to a switch 43 via a cable 35 so that the detent 34 can be disengaged from the toothed wheels 32 and 33 by operating the switch 43. The toothed wheels 32 and 33 can rotate. Hence, the racks 111 and 121 can be lifted or lowered, i.e., the armrest 4 can be lifted or lowered. The lifting of the armrest 4 is however not automatically conducted.

The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.

SUMMARY OF INVENTION

According to the present invention, telescopic support is provided for an armrest of a chair. The telescopic support includes a lower tube, an upper tube and a helical spring. The lower tube is installed on the chair. The upper tube telescopically receives the lower tube and supports the armrest. The helical spring is axially positioned in the upper tube and compressed between the upper tube and the lower tube for automatically and smoothly lifting the upper tube from the lower tube.

The primary advantage of the telescopic support of the present invention is the automatic and smooth lifting of the upper tube from the lower tube for the use of the helical spring.

Other advantages and features of the present invention will become apparent from the following description referring to the drawings.

BRIEF DESCRIPTION OF DRAWINGS

The present invention will be described through the illustration of two embodiments referring to the drawings.

FIG. 1 is a perspective view of a telescopic support for an armrest according to the first embodiment of the present invention.

FIG. 2 is an exploded view of the telescopic support shown in FIG. 1.

FIG. 3 is a cross-sectional view of the telescopic support along a line 3-3 in FIG. 1.

FIG. 4 is a cross-sectional view of the telescopic support in another position than shown in FIG. 3.

FIG. 5 is a cross-sectional view of the telescopic support in another position than shown in FIG. 4.

FIG. 6 is a perspective view of a telescopic support for an armrest according to the second embodiment of the present invention.

FIG. 7 is an exploded view of the telescopic support shown in FIG. 6.

FIG. 8 is a cross-sectional view of the telescopic support along a line 8-8 in FIG. 6.

FIG. 9 is a cross-sectional view of the telescopic support in another position than shown in FIG. 8.

FIG. 10 is a cross-sectional view of the telescopic support in another position than shown in FIG. 9.

FIG. 11 is a cross-sectional view of the telescopic support along a line 11-11 FIG. 6.

FIG. 12 is another cross-sectional view of the telescopic support in another position than shown in FIG. 9.

DETAILED DESCRIPTION OF EMBODIMENTS

Referring to FIG. 1, there is shown a telescopic support for an armrest according to a first embodiment of the present invention. The telescopic support includes a lower tube 70 and an upper tube 10.

Referring to FIG. 2, the upper tube 10 includes an enlarged upper portion 11, an opening 13 near the enlarged upper portion 11 and two stems 12 on the enlarged upper portion 11.

A retainer 60 consists of two identical halves 64. The retainer 60 includes an enlarged upper portion 62. The retainer 60 defines a channel 66 and two series of separate recesses 61 in communication with the channel 66.

The retainer 60 is inserted in the lower tube 70 except the enlarged upper portion 62 thereof positioned on an upper end of the lower tube 70. The retainer 60 is secured to the lower tube 70 by a screw 72 driven into a bore 63 defined in the retainer 60 through an aperture 72 defined in the lower tube 70.

A guide 20 includes a rod 29 and a platform 28 formed on the rod 23. The platform 28 defines two apertures 21 for receiving the stems 12 of the upper tube 10 when the plat form 28 is installed on the enlarged upper portion 11 of the upper tube 10 as the guide 20 is inserted in the upper tube 10. The platform 28 is secured to the enlarged upper portion 11 of the upper tube 10 by two threaded bolts 14.

The rod 29 defines a longitudinal groove 23 and two lateral apertures 25 in communication with the groove 23. A stem 24 is formed on the floor of the groove 23. A hook 27 is formed on the floor of the groove 23 near a lower end of the rod 29. A restraint 26 is formed on each of two walls of the groove 23. Two screws 22 are driven into the rod 29.

Positioned in the apertures 25 are two balls 50 for insertion into selected ones of the recesses 61 of the retainers 60.

A controller 30 includes a bent upper section 31, a bent lower section 32 and a wedge 35 formed between the bent upper section 31 and the bent lower section 32. The wedge 35 includes two inclined facets 36 for pushing the balls 50. The controller 30 defines a slot 33 between the bent upper section 31 and the wedge 35.

The controller 30 is movable in the groove 23 while the slot 33 receives the stem 24. A tension spring 37 includes an upper end hooked by the hook 32 and a lower end hooked by the hook 27 so as to bias the wedge 35 against the balls 50.

The bent upper section 31 of the controller 30 is exposed from the upper tube 10 through the opening 13. A handle 80 is connected to the bent upper section 31 of the controller 30.

The rod 29 is inserted through a helical compression spring 40 that is provided between the enlarged upper portion 62 of the retainer 60 and the screws 22 secured to the rod 29. Hence, the helical compressing spring 40 tends to lift the guide 20 and the upper tube 10 from the retainer 60 and the lower tube 70. An upper end of the helical compression 40 contacts the platform 28 at two symmetrical points centered at the rod 29. Therefore, the helical compression spring 40 can lift the upper tube 10 from the lower tube 70 very smoothly.

Referring to FIG. 3, the spring 37 pulls the controller 30 to a lower position. The wedge 35 comes between and pushes the balls 50 into selected ones of the recesses 61 of the retainer 60. Hence, the upper tube 10 cannot be moved towards and from the lower tube 70.

Referring to FIGS. 4 and 5, a user can lift the handle 80 so as to lift the controller 30. The wedge 35 is moved to an upper position so that it is not between the balls 50. The balls 50 can be moved from the recesses 61 of the retainer 60. The balls 50 will not fall from the apertures 25 because of the restraints 26 and the wedge 35. The upper tube 10 can be lowered and lifted relative to the lower tube 70. Now, the helical compression spring 40 can lift the upper tube 10 from the lower tube 70.

Referring to FIGS. 6 through 12, there is shown a telescopic support according to a second embodiment of the present invention. The telescopic support includes a lower tube 60B and an upper tube 10B.

The lower tube 60B defines two opposite series of apertures 62B in communication with one another. A cap 61B is installed on an upper end of the lower tube 60B.

The upper tube 10B includes two opposite apertures 13B defined therein, a cutout 15B defined in the edge of one of the apertures 13B and two lips 14B and 16B each formed around related one of the apertures 13B. The lip 16B includes a groove 161B on an internal side.

A controller 80B includes a latch 813B, a spring 82B, a threaded bolt 831B, a washer 832B and a cover 84B.

The latch 813B includes a button 81B formed at an end, a ridge 815B longitudinally formed thereon and two reduced sections 814B.

The cover 84B includes a plurality of slits 841B defined in the edge and a ridge 842B formed along the edge.

In assembly, the spring 40 is positioned in the upper tube 10B before the lower tube 60B is inserted in the upper tube 10B. The spring 40 is compressed between the platform 11B and the cap 61B. The spring 40 tends to lift the upper tube 10B from the lower tube 60B. A lower end of the spring 40 is fit on a portion of the cover 61B so that the position of the spring 40 is retained and that the upper end of the spring 40 is always located against the center of the platform 11B. Hence, the spring 40 can lift the upper tube 10B from the lower tube 60B smoothly.

The spring 82B is installed on the latch 813B that is inserted in the apertures 13B and the series of apertures 62B. The ridge 815B is positioned in the cutout 15B so that the latch 813B cannot be rotated. The button 81B is biased by the spring 82B. The threaded bolt 831B is driven in an opposite end of the latch 813B through the washer 832B. The cover 84B is positioned in the lip 16B. The slits 841 facilitate the insertion of the cover 84B. The ridge 842B is fit in the groove 161B so as to retain the cover 84B in the lip 16B.

The upper tube 10B can be moved between lower and upper positions on the lower tube 60B referring to FIGS. 8 and 10, respectively.

Referring to FIG. 11, the reduced sections 814B of the latch 813B are not located in the two series of apertures 62B so that the latch 813B cannot be moved in the two series of apertures 62B. Hence, the position of the upper tube 10B on the lower tube 60B is retained.

Referring to FIGS. 9 and 12, the button 81B is pressed so that the reduced sections 814B of the latch 813B are located in the two series of apertures 62B so that the latch 813B can be moved in the two series of apertures 62B. Therefore, the position of the upper tube 10B on the lower tube 60B can be changed.

The present invention has been described through the illustration of the embodiments. Those skilled in the art can derive variations from the embodiments without departing from the scope of the present invention. Therefore, the embodiments shall not limit the scope of the present invention defined in the claims. 

1. A telescopic support for an armrest of a chair, the telescopic support comprising a lower tube (70; 60B), an upper tube (10; 10B) for telescopically receiving the lower tube and supporting the armrest and a helical spring (40) axially positioned in the upper tube and compressed between the upper tube and the lower tube for automatic and smooth lifting of the upper tube from the lower tube.
 2. The telescopic support according to claim 1 comprising a guide (20) axially inserted in the upper tube for guiding the helical spring.
 3. The telescopic support according to claim 2 wherein the guide comprises a rod inserted through the helical spring.
 4. The telescopic support according to claim 3 wherein the rod comprises a groove (23) and at least one aperture (25) in communication with the groove, wherein the telescopic support comprises: a retainer (60) fit in the lower tube, the retainer comprising a channel (66) for receiving the rod and at least one series of recesses (61) in communication with the channel; at least one ball (50) positioned in the aperture of the rod for insertion into selected one of the recesses of the retainer so as to retain the guide and the upper tube in position relative to the retainer and the lower tube; and a controller (30) movable in the groove of the rod between a first position for pushing the ball into selected one of the recesses of the retainer and a second position for allowing the movement of the ball from the recesses.
 5. The telescopic support according to claim 4 comprising a handle (80) connected to the controller (30).
 6. The telescopic support according to claim 5 wherein the upper tube comprises an opening (13) through which the handle is exposed from the upper tube.
 7. The telescopic support according to claim 4 wherein the helical spring is compressed between an end of the retainer and two fasteners (22) secured to the rod.
 8. The telescopic support according to claim 4 wherein the controller comprises a wedge (35) for pushing the ball.
 9. The telescopic support according to claim 4 comprising a spring (37) for connecting the controller to the rod, thus tending to push the controller to the first section from the second section.
 10. The telescopic support according to claim 4 wherein the upper tube comprises an enlarged upper portion (11), wherein the guide comprises a platform (28) formed on the rod and positioned in the enlarged upper portion of the upper tube.
 11. The telescopic support according to claim 1 comprising a platform (11B) installed on the upper tube and a cap (61B) installed on the lower tube, wherein the helical spring is compressed between the cap and the platform.
 12. The telescopic support according to claim 11 wherein the helical spring comprises a lower end fit on a portion of the cap so that the helical spring is positioned.
 13. The telescopic support according to claim 12 wherein the upper tube comprises two lateral apertures (13B) defined therein, wherein the lower tube comprises two opposite series of continuous apertures (62) defined therein, wherein the telescopic support comprises a controller (80B) with a latch (813B) movably inserted in the lateral apertures of the upper tube and the two series of continuous apertures of the lower tube, wherein the latch (813B) comprises two reduced sections (814B) movable in the two series of continuous apertures of the lower tube for allowing the movement of the latch in and along the two series of continuous apertures of the lower tube.
 14. The telescopic support according to claim 13 wherein the controller comprises a button (81B) connected to an end of the latch, a washer (832B) and a fastener (831B) secured to an opposite end of the latch through the washer so that the button and the washer retain the latch in the upper tube.
 15. The telescopic support according to claim 14 wherein the controller comprises a spring (82B) compressed between the button and the upper tube for moving the reduced sections of the latch from the two series of continuous apertures of the lower tube.
 16. The telescopic support according to claim 14 wherein the latch comprises a ridge (815B) formed thereon, wherein the upper tube comprises a cutout (15B) defined in the edge of each of the lateral apertures for receiving the ridge of the latch so that the latch cannot be rotated in the upper tube.
 17. The telescopic support according to claim 14 wherein the upper tube comprises a lip (14B) around one of the lateral apertures for protecting the button.
 18. The telescopic support according to claim 14 wherein the upper tube comprises a lip (16B) around one of the lateral apertures for protecting the washer and the fastener.
 19. The telescopic support according to claim 18 wherein the controller comprises a cover (84B) installed on the lip for covering the washer and the fastener.
 20. The telescopic support according to claim 19 wherein the cover comprises a ridge (842B) formed thereon, wherein the lip defines, on an internal side, a groove (161B) for receiving the ridge of the cover. 